1. Field of Invention
The present invention relates to a projector including a plurality of optical modulation devices that modulate a plurality of colored light beams in accordance with image data, a prism that synthesizes the modulated light beams modulated by the plurality of optical modulation devices, and an optical-component casing to which the prism is to be fixed.
2. Description of Related Art
Hitherto, projectors have been known which include three optical modulation devices that modulate three colored light beams in accordance with image data, a crossed dichroic prism that synthesizes the modulated light beams modulated by the optical modulation devices, upper and lower light guides which are an optical-element casing that receives optical components such as lenses and mirrors, and a projection lens that enlarges and projects the luminous fluxes synthesized for projection by the prism.
Projectors are used for multimedia presentations in public meetings, such as conferences, academic meetings, and exhibitions. The projector is brought to the conference room, or is occasionally removed to another place, as needed. Therefore, the reduction in size of projectors has progressed.
In the projector using three optical modulation devices, as described above, the crossed dichroic prism is generally disposed in a concave part defined by the light guide, and is mounted to a structure to which the projection lens is to be fixed. Hitherto, the prism has been mounted in a manner such that screws passing through the structure at the lower part thereof engage with threaded holes formed in a supporting member disposed at the lower part of the prism.
However, in such a known projector, the thickness of the supporting member must be sufficiently increased so that the depth of the threaded holes ensures engagement of the threaded holes with the screws. Therefore, the problem is that it is difficult to reduce the profile and size of the projector by reducing the thickness of the supporting member so as to reduce the overall height of the projector.
Accordingly, an object of the present invention is to provide a projector with a reduced profile and size.
According to the present invention, a projector includes a plurality of optical modulation devices that modulate a plurality of colored light beams in accordance with image data; a prism that synthesizes the modulated light beams modulated by the optical modulation device; and an optical-component casing to which the prism is to be fixed. The prism is fixed to the optical-component casing via a supporting member that supports the prism. The supporting member is provided with a mounting part on which the prism is mounted and fixed thereto and a fixing part by which the mounting part is fixed to the optical-component casing. The fixing part is disposed at the periphery of the mounting part and at the outside of a side face of the prism.
The fixing part is provided with through-holes formed therein that receive screws or an engaging member that engages with the optical-component casing.
With the arrangement according to the present invention, the mounting part is not required to have a thickness sufficient for forming therein a fixing member such as threaded holes due to a fixing part disposed at the periphery of the mounting part and outside side faces of the prism for fixing the mounting part to the optical-component casing. Therefore, the thickness of the mounting part can be reduced, thereby reducing the overall height of the projector, whereby a projector having a low profile and a reduced size is made possible.
Since the fixing part for fixing the mounting part to the optical-component casing is disposed at the periphery of the mounting part and outside the side faces of the prism, screws can be applied from the side at which the prism is mounted, and the screws passing through through-holes formed in the fixing part engage with threaded holes formed in the optical-component casing associated with the through holes. With this arrangement, the projector can be manufactured easily compared with a conventional projector having a structure in which the screws must be passed through from the side opposite to the side to which a prism is mounted.
In the projector according to the present invention, the mounting part may be formed in a substantially rectangular shape in plan view having four comers, and the fixing part is preferably disposed at a pair of corners, opposing each other along one diagonal line therebetween, of the four corners of the mounting part.
With this arrangement, the mounting part can be fixed to the optical-component casing in a well-balanced manner, and is not moved out of position by an external force.
The optical-component casing is preferably provided with a supporting part disposed in a position thereof associated with the other diagonal line of the mounting part on which the fixing part is not provided, for supporting the bottom of the mounting part.
With this arrangement, the mounting part is supported by and fixed to the optical-component casing at four points on the crossing diagonal lines of the mounting part, whereby fixture by the supporting member is made firmer.
The prism and the optical modulation devices are preferably disposed in a concave part defined by the optical-component casing and having a shape of the letter U in plan view. A cover for covering the fixing part is preferably provided so as to conceal the same when the concave part is viewed from the upper face or from the bottom of the prism.
The prism and a plurality of the optical modulation devices are affixed in an adjusted state so that a plurality of images are projected so as to be focused at the same position on a projection area. However, when the prism is moved by the user after the position of the prism and the plurality of optical modulation devices is set, the position of the prism and the optical modulation devices is changed, whereby there is a risk of disturbing the images projected on the projection area, such as a screen.
Therefore, the cover is provided in the optical-component casing for covering the fixing part so as to conceal the same in plan view. When the fixing part is concealed by the cover, the fixing part cannot be touched from the outside, thereby preventing deterioration of the image quality of the adjusted projector from being caused.
The optical-component casing may be provided with a fan-mounting part to which a cooling fan for cooling the plurality of optical modulation devices is fixed, and the fan-mounting part preferably also serves as the cover.
With this arrangement, the cover is not required to be individually provided in the projector, thereby simplifying the structure, whereby the projector can be easily assembled.